Spiegel & Halberda (2011) Rapid fast-mapping abilities in 2-year-olds

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Abstract

Learning a new word consists of two primary tasks which have often been conflated into a single process: referent-selection, in which a child must determine the correct referent of a novel label, and referent-retention, or the ability to store this newly formed label-object mapping in memory for later use. Additionally, children must be capable of performing these tasks rapidly and repeatedly as they are frequently exposed to novel words during the course of natural conversation. Here, we used a preferential pointing task to investigate 2-year-olds' (N=72) ability to infer the referent of a novel noun from a single ambiguous exposure, and their ability to retain this mapping over time. Children were asked to identify the referent of a novel label on six critical trials distributed throughout the course of a 10-minute study involving many familiar and novel objects. On these critical trials, images of a known object and a novel object (e.g., a ball and a nameless artifact constructed in the lab) appeared on two computer screens and a voice asked the child to “point at the [e.g., glark].” Following label onset, children had only 3 seconds in which to infer the correct referent, point at it, and potentially store this new word-object mapping. In a final post-test trial, all previously labeled novel objects appeared and children were asked to point to one of them (e.g., Can you find the “glark”?). In order to succeed on this trial, children had to have initially mapped the novel labels correctly and retained these mappings over the course of the study. Despite the difficult demands of the current task children successfully identified the target object on the retention trial. We conclude that 2-year-olds are able to fast-map novel nouns during a brief, single exposure under ambiguous labeling conditions.

Methods

Children viewed 24 ambiguous labeling trials in which objects were presented side by side on separate monitors and a voice asked children to "Point at the [e.g. brush]". Over the course of the 5 min. study, children saw 36 familiar objects and 12 novel objects, 6 of which were given a novel label. Children had 3 seconds to identify the target, point to it, and store it in memory before the next trial began. After viewing 24 ambiguous labeling trials, children saw a single post-test trial in which we tested retention of a randomly chosen novel label (label asked for was counterbalanced across conditions). During this post-test, children saw all 6 of the previously labeled novel objects and were asked to identify one of them.

Results

Figure 1. Left - Percent of trials on which children successfully pointed to the target when prompted with a known or novel label during referent-selection (2-object display, chance =50%). Right - Percent of children who successfully pointed to the target novel object on the post-test referent-retention trial (6-object display, chance=16.67%). * indicates p

Supplemental Table Chi-square test of independence results comparing performance on the referent-retention post-test to correct pointing to target, reaction time to point to target (in ms), total % of time looking to target post label onset, and % increase looking to target post label-onset relative to pre-onset looking time to target on the label-object pairing which would later serve as the post-test target. Only a comparison between correct pointing and incorrect/no pointing showed a significant correlation to performance on referent-retention.

Halberda, J. & Feigenson, L. (2008). Developmental Change in the Acuity of the Number Sense: The Approximate Number System in 3-, 4-, 5-, and 6-Year-Olds and Adults. Developmental Psychology, 44 (5). [Demo]

Halberda, J., Taing, L. & Lidz, J. (2008). The development of “most” comprehension and its potential dependence on counting-ability in preschoolers. Language Learning and Development. [Demo]